Item stack size is now defined by ItemSlot, not ItemData

src/main/java/ru/windcorp/progressia/common/world/item/ItemData.java

@@ -17,87 +17,32 @@
  */
 package ru.windcorp.progressia.common.world.item;
 
-import ru.windcorp.progressia.common.state.IntStateField;
 import ru.windcorp.progressia.common.state.StatefulObject;
 import ru.windcorp.progressia.common.world.generic.ItemGeneric;
 
 /**
- * A collection of identical items identified by their ID, properties and
+ * An item identified by its ID and properties, able to reside in a slot.
- * amount, able to reside in a slot. Also known as an item stack.
- * <p>
- * An empty stack does not have an {@code ItemData} representation; stack size
- * is at least 1.
  */
 public abstract class ItemData extends StatefulObject implements ItemGeneric {
 
-	private final IntStateField size = field("Core:Size").setShared().ofInt().build();
-
 	public ItemData(String id) {
 		super(ItemDataRegistry.getInstance(), id);
-		size.setNow(this, 1);
 	}
 
 	/**
-	 * Returns the amount of individual items represented by this item stack.
+	 * Computes and returns the mass of a single unit (single item) of this
+	 * item.
 	 * 
-	 * @return the size of this stack
+	 * @return the mass of this item
 	 */
-	public final int getSize() {
+	public abstract float getMass();
-		return size.get(this);
-	}
-
-	/**
-	 * Sets the amount of items represented by this item stack.
-	 * 
-	 * @param size the new size of this stack, strictly positive
-	 */
-	public final void setSizeNow(int size) {
-		if (size <= 0) {
-			throw new IllegalArgumentException("size cannot be negative, given size " + size);
-		}
-		this.size.setNow(this, size);
-	}
-
-	/**
-	 * Computes and returns the total mass of this item stack. It is defined as
-	 * the item's unit mass (see {@link #getUnitMass()}) multiplied by the
-	 * amount of items in the stack.
-	 * 
-	 * @return the mass of this stack
-	 * @see #getUnitMass()
-	 */
-	public final float getMass() {
-		return getUnitMass() * getSize();
-	}
-
-	/**
-	 * Computes and returns the mass of a single unit (single item) of this item
-	 * stack.
-	 * 
-	 * @return the mass of a single item in this stack
-	 * @see #getMass()
-	 */
-	public abstract float getUnitMass();
-
-	/**
-	 * Computes and returns the total volume of this item stack. It is defined
-	 * as the item's unit volume (see {@link #getUnitVolume()}) multiplied by
-	 * the amount of items in the stack.
-	 * 
-	 * @return the mass of this stack
-	 * @see #getUnitVolume()
-	 */
-	public final float getVolume() {
-		return getUnitVolume() * getSize();
-	}
 
 	/**
 	 * Computes and returns the volume of a single unit (single item) of this
 	 * item stack.
 	 * 
-	 * @return the volume of a single item in this stack
+	 * @return the volume of this item
-	 * @see #getVolume()
 	 */
-	public abstract float getUnitVolume();
+	public abstract float getVolume();
 
 }

src/main/java/ru/windcorp/progressia/common/world/item/ItemDataSimple.java

@@ -19,23 +19,23 @@ package ru.windcorp.progressia.common.world.item;
 
 public class ItemDataSimple extends ItemData {
 
-	private final float unitMass;
+	private final float mass;
-	private final float unitVolume;
+	private final float volume;
 	
-	public ItemDataSimple(String id, float unitMass, float unitVolume) {
+	public ItemDataSimple(String id, float mass, float volume) {
 		super(id);
-		this.unitMass = unitMass;
+		this.mass = mass;
-		this.unitVolume = unitVolume;
+		this.volume = volume;
 	}
 	
 	@Override
-	public float getUnitMass() {
+	public float getMass() {
-		return unitMass;
+		return mass;
 	}
 	
 	@Override
-	public float getUnitVolume() {
+	public float getVolume() {
-		return unitVolume;
+		return volume;
 	}
 
 }

src/main/java/ru/windcorp/progressia/common/world/item/ItemSlot.java

@@ -31,6 +31,7 @@ import ru.windcorp.progressia.common.state.IOContext;
 public class ItemSlot implements Encodable {
 
 	private ItemData contents;
+	private int amount;
 
 	/**
 	 * Retrieves the contents of this slot.
@@ -43,29 +44,87 @@ public class ItemSlot implements Encodable {
 
 	/**
 	 * Sets the new contents of this slot. If an item stack was present
-	 * previously, it is discarded.
+	 * previously, it is discarded. If the contents are {@code null}, the slot
+	 * is emptied.
+	 * <p>
+	 * When the slot receives non-null contents, the new amount must be a
+	 * positive integer. When the slot is emptied, {@code amount} must be 0.
 	 * 
 	 * @param contents the new contents of this slot or {@code null} to clear
 	 *                 the slot
+	 * @param amount   the amount of items to set.
+	 *                 {@code (amount == 0) == (contents == null)} must be true.
 	 */
-	public synchronized final void setContents(ItemData contents) {
+	public synchronized final void setContents(ItemData contents, int amount) {
 		this.contents = contents;
+		this.amount = amount;
+		
+		checkState();
+	}
+
+	/**
+	 * Sets the amount of items stored in this slot.
+	 * <p>
+	 * Setting the amount to zero also erases the slot's contents.
+	 * 
+	 * @param amount the new amount
+	 */
+	public synchronized void setAmount(int amount) {
+		setContents(amount == 0 ? null : contents, amount);
+	}
+	
+	/**
+	 * Clears this slot
+	 */
+	public synchronized void clear() {
+		setContents(null, 0);
+	}
+
+	/**
+	 * Retrieves the amount of items stored in this slot. If not items are
+	 * present, this returns 0.
+	 * 
+	 * @return the amount of items stored
+	 */
+	public synchronized int getAmount() {
+		return amount;
+	}
+	
+	public synchronized boolean isEmpty() {
+		return amount == 0;
+	}
+	
+	private synchronized void checkState() {
+		if ((contents == null) != (amount == 0)) {
+			if (contents == null) {
+				throw new IllegalArgumentException("Contents is null but amount (" + amount + ") != 0");
+			} else {
+				throw new IllegalArgumentException("Contents is " + contents + " but amount is zero");
+			}
+		}
+		
+		if (amount < 0) {
+			throw new IllegalArgumentException("amount is negative: " + amount);
+		}
 	}
 
 	@Override
 	public synchronized void read(DataInput input, IOContext context) throws IOException {
-		if (input.readBoolean()) {
+		amount = input.readInt();
+		if (amount != 0) {
 			String id = input.readUTF();
 			contents = ItemDataRegistry.getInstance().create(id);
 			contents.read(input, context);
 		} else {
 			contents = null;
 		}
+		
+		checkState();
 	}
 
 	@Override
 	public synchronized void write(DataOutput output, IOContext context) throws IOException {
-		output.writeBoolean(contents != null);
+		output.writeInt(amount);
 		if (contents != null) {
 			output.writeUTF(contents.getId());
 			contents.write(output, context);
@@ -76,6 +135,8 @@ public class ItemSlot implements Encodable {
 	public void copy(Encodable destination) {
 		ItemSlot slot = (ItemSlot) destination;
 
+		slot.amount = this.amount;
+		
 		if (this.contents == null) {
 			slot.contents = null;
 		} else {

src/main/java/ru/windcorp/progressia/server/PlayerManager.java

@@ -27,7 +27,6 @@ import ru.windcorp.progressia.common.util.crash.CrashReports;
 import ru.windcorp.progressia.common.world.entity.EntityData;
 import ru.windcorp.progressia.common.world.entity.EntityDataPlayer;
 import ru.windcorp.progressia.common.world.entity.EntityDataRegistry;
-import ru.windcorp.progressia.common.world.item.ItemData;
 import ru.windcorp.progressia.common.world.item.ItemDataRegistry;
 import ru.windcorp.progressia.server.events.PlayerJoinedEvent;
 import ru.windcorp.progressia.test.TestContent;
@@ -66,16 +65,8 @@ public class PlayerManager {
 		
 		player.getInventory().addSlots(10);
 		
-		ItemData stack = ItemDataRegistry.getInstance().create("Test:MoonTypeIceCream");
+		player.getInventory().getSlot(3).setContents(ItemDataRegistry.getInstance().create("Test:MoonTypeIceCream"), 5);
-		stack.setSizeNow(5);
+		player.getInventory().getSlot(6).setContents(ItemDataRegistry.getInstance().create("Test:MoonTypeIceCream"), 1);
-		player.getInventory().getSlot(3).setContents(stack);
-		
-		player.getInventory().getSlot(6).setContents(ItemDataRegistry.getInstance().create("Test:MoonTypeIceCream"));
-		
-		player.getLeftHand().getSlot(0).setContents(ItemDataRegistry.getInstance().create("Test:MoonTypeIceCream"));
-		stack = ItemDataRegistry.getInstance().create("Test:MoonTypeIceCream");
-		stack.setSizeNow(64);
-		player.getRightHand().getSlot(0).setContents(stack);
 
 		player.setPosition(getServer().getWorld().getGenerator().suggestSpawnLocation());
 		player.setUpVector(new Vec3(0, 0, 1));

src/main/java/ru/windcorp/progressia/test/inv/InventoryScreen.java

@@ -148,10 +148,13 @@ public class InventoryScreen extends Component {
 			ItemSlot from = ((DecoratedSlotComponent) button).getSlot();
 
 			ItemData fromData = from.getContents();
+			int fromAmount = from.getAmount();
+			
 			ItemData toData = to.getContents();
+			int toAmount = to.getAmount();
 
-			from.setContents(toData);
+			from.setContents(toData, toAmount);
-			to.setContents(fromData);
+			to.setContents(fromData, fromAmount);
 
 			requestReassembly();
 

src/main/java/ru/windcorp/progressia/test/inv/SlotComponent.java

@@ -39,8 +39,8 @@ public class SlotComponent extends Component {
 	
 	private ItemRenderable itemRenderer = null;
 
-	private int sizeDisplayInt = 0;
+	private int amountDisplayInt = 0;
-	private String sizeDisplayString = "";
+	private String amountDisplayString = "";
 
 	public SlotComponent(String name, ItemContainer container, int index) {
 		super(name);
@@ -51,7 +51,7 @@ public class SlotComponent extends Component {
 		setPreferredSize(side, side);
 
 		Font sizeFont = new Font().deriveOutlined().withScale(1);
-		addChild(new DynamicLabel(name + ".Size", sizeFont, () -> sizeDisplayString, side));
+		addChild(new DynamicLabel(name + ".Size", sizeFont, () -> amountDisplayString, side));
 
 		setLayout(new LayoutAlign(0, 0, 0));
 	}
@@ -74,17 +74,17 @@ public class SlotComponent extends Component {
 
 		if (contents == null) {
 			itemRenderer = null;
-			sizeDisplayInt = 0;
+			amountDisplayInt = 0;
-			sizeDisplayString = "";
+			amountDisplayString = "";
 		} else {
 			if (itemRenderer == null || itemRenderer.getData() != contents) {
 				itemRenderer = ItemRenderRegistry.getInstance().get(contents.getId()).createRenderable(contents);
 			}
 
-			int newSize = contents.getSize();
+			int newAmount = getSlot().getAmount();
-			if (newSize != sizeDisplayInt) {
+			if (newAmount != amountDisplayInt) {
-				sizeDisplayInt = newSize;
+				amountDisplayInt = newAmount;
-				sizeDisplayString = newSize == 1 ? "" : Integer.toString(newSize);
+				amountDisplayString = newAmount == 1 ? "" : Integer.toString(newAmount);
 			}
 		}
 	}